[Studies on antigenicity of difluprednate--antigenicity of difluprednate, phototoxicity and photocontact sensitivity of difluprednate ointment and cream].

The antigenicity of difluprednate, phototoxicity and photocontact sensitivity of difluprednate ointment and cream were studied in guinea pigs and mice. The results in this study were as follows. Guinea pigs immunized with difluprednate emulsified with Freund's complete adjuvant did not exhibit the systemic anaphylaxis and the delayed type hypersensitivity by the elicitation with either difluprednate alone or difluprednate-BSA conjugate. The antisera obtained from these guinea pigs did not show the positive response in the homologous 4-hour PCA reaction and the passive hemagglutination test against the challenge of the same antigens described above. In the maximization test, guinea pigs immunized with difluprednate did not show the contact sensitivity when elicited with difluprednate suspended in saline. Guinea pigs applied difluprednate ointment did not show positive contact sensitivity by the elicitation with difluprednate ointment and ointment base. The antisera obtained from mice immunized with difluprednate and difluprednate-OVA conjugate absorbed to Al (OH)3 gel did not give the positive response in the 72-hour PCA reaction against the challenge of either difluprednte alone or difluprednate-BSA conjugate. In the phototoxicity and photocontact sensitivity test, 0.05% difluprednate ointment and 0.05% difluprednate cream did not show positive reactions in guinea pigs, although very slight erythema was caused by the primary irritancy of cream base, with or without irradiation of ultraviolet ray (320-400 nm).